Call push asyncly after readableStream.on('data', ...) will cause error.

[07akioni]

• Version: v14.17.0
• Platform: Darwin 20.3.0 Darwin Kernel Version 20.3.0: Thu Jan 21 00:07:06 PST 2021; root:xnu-7195.81.3~1/RELEASE_X86_64 x86_64
• Subsystem:

What steps will reproduce the bug?

const { Readable } = require("stream");
const readableStream = new Readable();
setTimeout(() => {
  readableStream.push("chunk");
  readableStream.push(null);
}, 1000);
readableStream.on("data", () => {
  console.log("whatever");
});

internal/streams/readable.js:642
  throw new ERR_METHOD_NOT_IMPLEMENTED('_read()');
  ^

Error [ERR_METHOD_NOT_IMPLEMENTED]: The _read() method is not implemented
    at Readable._read (internal/streams/readable.js:642:9)
    at Readable.read (internal/streams/readable.js:481:10)
    at resume_ (internal/streams/readable.js:977:12)
    at processTicksAndRejections (internal/process/task_queues.js:82:21) {
  code: 'ERR_METHOD_NOT_IMPLEMENTED'
}

How often does it reproduce? Is there a required condition?

Everytimes.

What is the expected behavior?

I'm not quite sure but I won't expect it to have errors after reading the docs.

What do you see instead?

Additional information

[bl-ue]

cc @nodejs/streams

[aduh95]

cc @nodejs/streams

[ronag]

You need to implement the _read method or at least pass a stub, it's not optional. I think the docs are clear on this (haven't checked)?

[mcollina]

This is clearly documented.